题解 | #占空比50%的奇数分频#

四个下降沿高电平 四个上升沿低电平 一个计数器记录电平变换，并控制计数器工作

`timescale 1ns/1ns

module odo_div_or ( input wire rst , input wire clk_in, output wire clk_out7 );

reg [2:0] count1 = 0;
reg [2:0] count2 = 0;
reg flag = 0;
reg waveout = 0;

assign clk_out7 = flag;

always@(posedge clk_in or negedge rst)begin // low
    if(rst == 1'b0)begin
        count1 <= 3'd0;
    end
    else begin
        if(count1 >= 3'd3)begin
            count1 <= 3'd0;
            flag <= 1'b0;
        end
        else begin
            if(flag == 1'b1)
                count1 <= count1 + 1;
        end
    end
end

always@(negedge clk_in or negedge rst)begin // high
    if(rst == 1'b0)begin
        count2 <= 3'd0;
        flag <= 1'b0;
    end
    else begin
        if(count2 >= 3'd3)begin
            count2 <= 3'd0;
            flag <= 1'b1;
        end
        else begin
            if(flag == 1'b0)
                count2 <= count2 + 1;
        end
    end
end

endmodule